docs: def Stichlmair_wet(Vg, Vl, rhog, rhol, mug, voidage, specific_area, C1, C2, C3, H=1):
      r'''Calculates dry pressure drop across a packed column, using the
      Stichlmair [1]_ correlation. Uses three regressed constants for each
      type of packing, and voidage and specific area. This model is for irrigated
      columns only.
  
      Pressure drop is given by:
  
      .. math::
          \frac{\Delta P_{irr}}{H} = \frac{\Delta P_{dry}}{H}\left(\frac
          {1-\epsilon + h_T}{1-\epsilon}\right)^{(2+c)/3}
          \left(\frac{\epsilon}{\epsilon-h_T}\right)^{4.65}
  
      .. math::
          h_T = h_0\left[1 + 20\left(\frac{\Delta Pirr}{H\rho_L g}\right)^2\right]
  
      .. math::
          Fr_L = \frac{V_L^2 a}{g \epsilon^{4.65}}
  
      .. math::
          h_0 = 0.555 Fr_L^{1/3}
  
      .. math::
          c = \frac{-C_1/Re_g - C_2/(2Re_g^{0.5})}{f_0}
  
      .. math::
          \Delta P_{dry} = \frac{3}{4} f_0 \frac{1-\epsilon}{\epsilon^{4.65}}
          \rho_G \frac{H}{d_p}V_g^2
  
      .. math::
          f_0 = \frac{C_1}{Re_g} + \frac{C_2}{Re_g^{0.5}} + C_3
  
      .. math::
          d_p = \frac{6(1-\epsilon)}{a}
  
      Parameters
      ----------
      Vg : float
          Superficial velocity of gas, Q/A [m/s]
      Vl : float
          Superficial velocity of liquid, Q/A [m/s]
      rhog : float
          Density of gas [kg/m^3]
      rhol : float
          Density of liquid [kg/m^3]
      mug : float
          Viscosity of gas [Pa*s]
      voidage : float
          Voidage of bed of packing material []
      specific_area : float
          Specific area of the packing material [m^2/m^3]
      C1 : float
          Packing-specific constant []
      C2 : float
          Packing-specific constant []
      C3 : float
          Packing-specific constant []
      H : float, optional
          Height of packing [m]
  
      Returns
      -------
      dP : float
          Pressure drop across irrigated packing [Pa]
  
      Notes
      -----
      This model is used by most process simulation tools. If H is not provided,
      it defaults to 1. If Z is not provided, it defaults to 1.
      A numerical solver is used and needed by this model. Its initial guess
      is the dry pressure drop. Convergence problems may occur.
      The model as described in [1]_ appears to have a typo, and could not match
      the example. As described in [2]_, however, the model works.
  
      Examples
      --------
      Example is from [1]_, matches.
  
      >>> Stichlmair_wet(Vg=0.4, Vl = 5E-3, rhog=5., rhol=1200., mug=5E-5,
      ... voidage=0.68, specific_area=260., C1=32., C2=7., C3=1.)
      539.8768237253518
  
      References
      ----------
      .. [1] Stichlmair, J., J. L. Bravo, and J. R. Fair. "General Model for
         Prediction of Pressure Drop and Capacity of Countercurrent Gas/liquid
         Packed Columns." Gas Separation & Purification 3, no. 1 (March 1989):
         19-28. doi:10.1016/0950-4214(89)80016-7.
      .. [2] Piche, Simon R., Faical Larachi, and Bernard P. A. Grandjean.
         "Improving the Prediction of Irrigated Pressure Drop in Packed
         Absorption Towers." The Canadian Journal of Chemical Engineering 79,
         no. 4 (August 1, 2001): 584-94. doi:10.1002/cjce.5450790417.
      '''
      dp = 6.0*(1.0 - voidage)/specific_area
      Re = Vg*rhog*dp/mug
      f0 = C1/Re + C2/Re**0.5 + C3
      dP_dry = 3/4.*f0*(1-voidage)/voidage**4.65*rhog*H/dp*Vg*Vg
      c = (-C1/Re - C2/(2*Re**0.5))/f0
      Frl = Vl**2*specific_area/(g*voidage**4.65)
      h0 = 0.555*Frl**(1/3.)
      def to_zero(dP_irr):
          hT = h0*(1.0 + 20.0*(dP_irr/H/rhol/g)**2)
          err = dP_dry/H*((1-voidage+hT)/(1.0 - voidage))**((2.0 + c)/3.)*(voidage/(voidage-hT))**4.65 -dP_irr/H
          return err
      return float(newton(to_zero, dP_dry))